Amount Of Cu Research Articles

Effect of Adding Minor Cu Amounts on Stability of Constituent Phases in Al<sub>x</sub>CrFeMnNi High Entropy Alloy Microstructure

A family of AlxCuyCrFeMnNi (x=0, 0.15, 0.3, 0.6, 0.9 and y=0, 0.07, 0.14) high entropy alloys (HEA) were arc cast and then heat treated for 24h at 1100֯C-1150֯C followed by water quench. The microstructure of low Al alloys (Al0Cux and Al0.15Cux) consisted of FCC and BCC phases. Al0.3Cux showed an additional ordered precipitate phase. High Al alloys (Al0.6Cux and Al0.9Cux) consisted of two BCC phases rich in Cr-Fe and Ni-Al. In the present study, the phases formed in the microstructures were evaluated in light of valence electron concentration (VEC), Hume-Rothery (H-R) and degree of partitioning. Although VEC successfully predicts the impact of Al and Cu on the trend of FCC-BCC phase formation, the parameter does not accurately predict the structure of high Al alloys. A good agreement was observed between H-R rules prediction and the experiments which might be ascribed to the high temperature equilibrium phases developed by the heat treatment. As per these criteria, increasing Cu (up to 3at.%) and decreasing Al promote formation of solid solution phases. Adding minor amounts of Cu avoids the Cu partitioning that besets high Cu HEAs.

Nitrogen promoted electron transfer to create highly active Cu2+ and Mn3+ sites for efficient catalytic ozonation of Ammonia over copper and nitrogen co-doped Cryptomelane-Type manganese oxide at ambient temperature

Eliminating ammonia (NH3) from high-humidity exhaust gases by catalytic oxidation is a great challenge, especially at low temperatures. Herein, Cu and N co-doped cryptomelane-type manganese oxide (Cu-N-OMS-2) catalysts with high active Cu2+ and Mn3+ sites were synthesized and tested for catalytic ozonation of NH3 at 30 °C. The optimal Cu0.05-N2-OMS-2 catalyst exhibited 93.8 % NH3 conversion, 91.7 % O3 conversion, and 92.1 % N2 selectivity when the relative humidity (RH) was 40 %, whereas OMS-2 only demonstrated 39.3 %, 44.0 % and 83.1 %. Additionally, NH3 and O3 conversion at high RH could be recovered with just a basic water-washing, indicating that Cu0.05-N2-OMS-2 catalyst possessed outstanding renewable properties. The results of characterization revealed that N doping increased the amount of Cu fixed on the catalyst surface and promoted the electron transfer from Cu to Mn, resulting in an increase in electron-poor Cu2+ and electron-rich Mn3+ in Cu-N-OMS-2. In dry conditions, the Mn3+ sites provided O3 with electrons to form adsorbed oxygen species and •O2–, which were essential for oxidation of adsorbed NH3. The electron-poor Cu2+ sites combined with H2O and O3 to form Cu-OH and •HO3, which facilitated the generation of •OH and •O2–, thereby improving the stability under humid conditions. This study provides a new theoretical guidance for the efficient removal of NH3 in industrial exhaust gases.

Effect of Annealing Process on the Morphological, Optical and Electrical Properties of Cu:MnO Films Prepared by PLD Technique

In this study, Nd:YAG laser pulses with a wavelength of 1064 nm, a power of 500 mJ, a pulse width of 9 ns, and a repetition frequency of 6 Hz were used to hit a manganese oxide (MnO) target surface 300 times. Pure MnO and copper Cu-doped MnO (Cu:MnO) with different amounts of Cu (0.03, 0.05, 0.07, and 0.09 wt%) produced by PLD were studied. Cu:MnO thin films were annealed at 473 K, and their morphological, optical, and electrical characteristics were studied. The results of the atomic force microscopic (AFM) investigation of morphological properties showed that Cu dopant impacted the creation of roughness and particle size in MnO2 films. The optical transmission was examined using a UV-Vis spectrophotometer. The highest optical absorption was noted at 0.09 dopant content. The dielectric constants' real (εr) and imaginary (εi) components, as well as the extinction coefficient (k), refractive index (n), and other optical constants, were studied. At an annealing temperature of (473 K), Hall effect studies demonstrate that all produced films exhibit a P-type conductivity.

Exploring the impact of copper excess on soybean genotypes: insights from root morphology and plant ionome

ABSTRACT Global growing demand for food production and commodity increased prices stimulate soybean cultivation in Brazil even in areas with high soil copper (Cu) concentration. This can promote root injuries and nutritional imbalances, reducing the growth and yield of Cu-sensitive soybean genotypes. The study aimed to investigate soybean genotypes potentially adapted to Cu-contaminated zones. Four soybean genotypes (NA 5909, DM 5958, M 6410, and DM 6563) and three Cu concentrations in the nutrient solution (0.03, 1.2, and 2.4 mg L−1) were evaluated. Root and shoot dry mass, root morphology, and inorganic composition of plant tissues were determined. The shoot and root dry mass was affected by Cu excess, especially in DM 5958 genotype, which decreased by up to 46%. Otherwise, the DM 6563 genotype stood out for growing satisfactorily under Cu excess and keeping significant amounts of Cu in the belowground biomass. The Cu excess promoted root thickening and shortening, and altered the ionome of soybean plants by decreasing the concentrations of K, Ca, Mg, and Fe, yet increasing P and N, which caused decreased plant growth. Finally, our outcomes indicated DM 6563 genotype exhibits promising traits for Cu phytostabilization, making it preferable for cultivation in Cu-contaminated areas.

Tourmaline as a petrogenetic indicator highlighted in a multicoloured crystal from the gem deposit of Mavuco, Alto Ligoña pegmatite district, NE Mozambique

Abstract A rounded fragment of a multicoloured tourmaline crystal (2.5 cm diameter), collected from the secondary gem deposit of Mavuco, Alto Ligoña pegmatite district, Mozambique, has been investigated using a multi-analytical approach, with the objective of reconstructing its growth history. The sample represents a core-to-rim section, perpendicular to the c axis, of a crystal characterised by a variety of colours. These change from a black core to an intermediate zone with a series of colours, yellow, blue–green and purple, to a final dark-green prismatic overgrowth. These changes are the result of a wide variation in Fe, Mn, Ti and Cu concentrations and their redox state. The black core is characterised by enrichment in Fe and Mn, with iron present in its divalent state. The yellow zone shows a progressive depletion in Fe and its colouration is caused by Mn2+ and Mn2+-Ti4+ IVCT interactions. The progressive decrease in Mn coupled with the absence of Ti, and the lack of Fe, implies that Cu2+ acts as the only chromophore in the pale blue–green zone. The dominant colour-causing agent of the purplish zone is Mn3+, denoting a change in redox environment; however, even though the amount of Cu remains significant, its chromophore effect is obscured by Mn3+. The dark-green prismatic overgrowth, characterised by a sharp increase in Fe, Mn and also Ca, is interpreted as a late-stage partial re-opening of the geochemical system. This occurrence could potentially be related to mechanical instability of the cavity in which the crystal grew.

Influence of Cu doping on the functionality of spray coated SnS2 thin films and its photocatalytic degradation of dyes and antibacterial activity

Tin sulfide (SnS2) is a material known for its effective photocatalytic activity due to its affordability and wide light spectrum response. To enhance and optimize its optical and chemical characteristics, doping is a straightforward approach that can improve its photocatalytic efficiency. This work focuses on the effect of Cu doping on the structural, optical, and photocatalytic properties of the thin films prepared by the spray-coating approach. XRD confirms the hexagonal SnS2 structure. As the amount of Cu added increases, the crystallite size decreases while dislocation density rises. The XPS findings show that a low concentration of copper (2%) within the SnS2 thin films exhibits both high solubility and exclusively a monovalent state, in contrast to the 4% concentration. The effective band gap is in the range of 1.9–2.2 eV. SEM image reveals a variety of morphologies, and the porosity is reduced with increasing Cu doping. Furthermore, the FTIR study confirms the Sn-S bond present at 753 cm−1. EPR studies reveal the existence of sulfur vacancies in Cu-doped SnS2. Mechanical properties were also affected, with an observed decrease in microhardness as the dopant concentration increased. The photocatalytic activity of the samples is studied by photocatalytic degradation of malachite green and Congo red dyes under visible light irradiation. Additionally, their antibacterial effect against Escherichia coli was examined. This study shows that an optimal amount of Cu doping can significantly increase the photocatalytic performance of SnS2 for efficiently decomposing organic pollutants and enhancing antibacterial activities.

Application of handheld/portable spectroscopic tools to the identification, inner stratigraphy and mapping of archaeological metal artefacts

Field handheld/portable instrumentations, such as in-situ geochemical analyzers, have the potential to assist efficiently targeted geochemical archaeometry campaigns in detecting and quantifying specific elements. Non-destructive portable energy dispersive x-ray fluorescence and micro-destructive handheld laser-induced breakdown spectroscopy (LIBS) instrumentation were utilized to investigate the elemental composition, internal stratigraphy by depth profiling and microscale compositional mapping of five copper and two iron alloy artefacts collected from various ancient graves in the Minervino Murge area, Apulia, Italy. The primary elements identified by both techniques included Cu, Sn and Pb in copper alloys, and Fe with minor amounts of Cu and Pb in iron alloys. Furthermore, the elements Al, Ca, Si, Mg, Na and K, mostly originated from soil contamination, and the trace elements Sb, Ni and Zn were detected. The satisfactory performance of both techniques was assessed by their capacity to provide reproducible elemental composition data. Finally, the depth profile and mapping achieved by LIBS contributed to understanding the metal processing and history of the objects studied, so confirming both techniques to be robust analytical tools in outdoor archaeology and archaeometry campaigns.

Effects of Vermicomposting on Compost Quality and Heavy Metals：A Meta-analysis

In order to comprehensively evaluate the effects of vermicomposting on compost quality and the conversion of heavy metals under different control conditions, 109 studies were reviewed. The effects of earthworm species, pre-compost time, ventilation methods, initial C/N, initial pH, and initial moisture of the raw materials on compost quality and the heavy metal toxicity were quantitatively discussed during the vermicomposting process through Meta-analysis. The results showed that the six subgroups of factors all showed obvious influences on the compost quality and heavy metal toxicity. After vermicomposting, the contents of NO3--N (116.2%), TN (29.1%), TP (31.2%), and TK (15.0%) were significantly increased, whereas NH4+-N (-14.8%) and C/N (-36.3%) were significantly decreased. Meanwhile, the total amount of Cu and Cr of the final compost and their bioavailability were significantly reduced. Considering the influences of grouping factors on compost quality and heavy metals, it is recommended to adjust the initial moisture of pile materials to 70%-80%, C/N to 30-85, and pH to 6-7 and to conduct pre-composting for 0-15 d; additionally, vermicomposting should be naturally placed when the composting is aimed at promoting the compost quality. If the main purpose is to weaken the perniciousness of heavy metals in the raw material, it is recommended to adjust the initial moisture of the material to 50%-60%, C/N to less than 30, and pH to 7-8; to conduct no pre-compost; regularly turn the piles; and use the earthworm Eudrilus eugeniae for vermicomposting.

Study of Cu-doped zirconia toughened alumina ceramics (Cu-ZTA) subject to lubrication behaviors for arthroplasty

Zirconia-toughened alumina (ZTA) is widely applied in total hip arthroplasty (THA). However, problems with insufficient fracture toughness and lubrication remain, leading to wear, squeaking, and fracturing. In this study, the Cu doping of ZTA (Cu-ZTA) is proposed to solve these problems. To further promote the use of Cu-ZTA, the role of Cu doping on its tribological properties must be studied. In this study, the microstructure, mechanical properties, and stability capacity in a physiological environment, as well as the tribological behaviors of Cu-ZTA in phosphate-buffered saline (PBS) and bovine serum albumin (BSA), were systematically studied with varying amounts of Cu. The results demonstrated that holes and soft Cu-rich phases appeared, and grains grew after Cu doping, causing a decrease in hardness. The fracture toughness increased after Cu doping because the Cu-rich particles formed “bridges” during crack propagation and release energy. The incorporation of Cu improved the stability of ZTA in physiological environments, which enhanced the long-term stability of Cu-ZTA. The protein adsorption results indicated that a higher hydrophobicity and roughness contributed to a greater protein adsorption on the Cu-ZTA surfaces after Cu incorporation. In the BSA solution, the 5.0 wt% Cu-ZTA ceramics achieved a lower coefficient of friction (COF) and wear rate compared to ZTA, and a higher protein adsorption and formation of the denatured protein layer catalyzed by Cu ions in the wear track during friction, thus clearly improving the tribological properties of the Cu-ZTA.

Flexible Copper Films Modification via Spontaneous Reduction of Aryldiazonium Gold Salts: Unraveling Surface Properties and Energy Profile.

In this study, we report the modification of flexible copper films via the spontaneous reduction of aryldiazonium gold salts [X-4-C6H4N≡N]AuCl4 (X═COOH, NO2). The electroless modification involves dipping of flexible copper films in the aryldiazonium gold solutions for a few seconds, under ambient conditions, followed by a washing step with deionized water to obtain a mechanically robust gold-aryl coating. The chemical composition, morphology, electronic structure, and optical properties of the gold-aryl layer and the flexibility of the modified copper films are supported by the results from X-ray photoelectron spectroscopy (XPS), electrochemistry, contact angle, scanning electron microscopy (SEM), and ultraviolet photoelectron spectroscopy (UPS). XPS surface analysis showed metallic gold in addition to C-C, C-O/C-N, and C═O functional groups from the grafted aryls. Cu 2p showed metallic copper as a major component and a small amount of Cu(II) ions. Wettability studies showed that Au-COOH@Cu increased the contact angle of the bare copper films from 68.0 ± 0.7° to 82.0° ± 0.7°, while Au-NO2@Cu increased the contact angle to 134.0° ± 0.3°. UPS energy profile analysis of [HOOC-4-C6H4N≡N]AuCl4 (valence band maximum = 1.91 eV) exhibited greater reducibility than [O2N-4-C6H4N≡N]AuCl4 (valence band maximum = 2.91 eV). The lower ionization potential of [HOOC-4-C6H4N≡N]AuCl4 (IP = 4.33 eV) enhanced the reactivity upon copper film contact, potentially inducing efficient energy level alignment, compared with [O2N-4-C6H4N≡N]AuCl4 (IP = 5.62 eV). UPS results were further supported by electrochemistry investigation which revealed that [HOOC-4-C6H4N≡N]AuCl4 is easily reducible compared with [O2N-4-C6H4N≡N]AuCl4. The findings presented here hold significant implications for developing flexible copper films and pave the way for future advancements in electronic material modification for industrial applications.

Ecological risk, source apportionment, and influencing factors of heavy metals in soil in a typical lead-zinc mining watershed, Guangxi, China

Soil contamination by heavy metals (HMs) leads to significant decreases in soil ecosystem quality, seriously threatening human survival and development. Studies on soil HMs have focused on the sources, distributions, and influencing factors. However, soil HM migration and speciation, which indirectly affect HM distributions and their ecological risks, have often been overlooked. In this study, we investigated the links between the sources, distributions, and influencing factors of soil HMs, as well as their ecological risks at several levels, by analyzing soil samples collected from a Pb-Zn mining area. Soil column experiments were also performed to assess Pb leaching in the soil. The results indicate that soil HMs accumulated in front of the mountain river outlets, at the entrance of the underground river, and at soil depths of 0–40 cm. Cd and Pb were the main contributors to the high ecological risk in the soil, and As and Cr were the main contributors to cancer risk. The source analysis indicates that mining and smelting activities were the main sources of total soil HMs (32.55%), as well as the main sources of Sb (83.43%), Pb (68.65%), and Cu (45.37%). Mining activity and continuous riverine transport were the main sources of Cd (69.93%) and Zn (52.38%). These anthropogenic sources have major impacts on the ecological environment in the study area. Factors such as pH, clay and silt contents, soil organic matter content, and cation exchange capacity influenced the distributions and total amounts of Cu, Mn, Zn, and Pb species.

Cu microvia filling by pulse-reverse electrodeposition with a single accelerator

Cu electrodeposition processes are widely employed to achieve defect-free interconnections in electronic devices. Typically, combinations of three additives—an accelerator, a suppressor, and a leveler—are used for bottom-up filling of Cu in microscaled features. However, the use of multiple additives adds complexity to electrolyte maintenance and can lead to reliability issues in the process. To address this challenge, we have developed a single-accelerator filling technique using pulse-reverse electrodeposition for microvias. During pulse-reverse electrodeposition, the anodic steps produce a large amount of Cu+ ions near the electrode surface. These Cu+ ions can form complexes with Cl− ions or CuCl layers, thereby enhancing the adsorption of the accelerator, SPS. This phenomenon depends on the electrolyte convection. Under strong forced convection, Cu-Cl species are removed, leading to subsequent deactivation of SPS, whereas Cu-Cl species remain stable under mild convection conditions. Based on this convection-dependent behavior of SPS and Cl, Cu electrodeposition is promoted at the bottom of microvias while the SPS is selectively deactivated outside the microvias where the strong electrolyte motion exists. As a result, without any polymeric suppressor and organic leveler, the microvias are successfully filled with Cu.

Accumulation and Potential Remediation of Copper in Golf Course Putting Greens

The objective of this study was to determine the potential accumulation of copper (Cu) within a USGA golf green profile and analyze potential remediation techniques of soils containing toxic Cu concentrations. Accumulation study utilized: copper phthalocyanine pigment (Par), copper hydroxide (Junction DF), varying concentrations of copper sulfate (CuSO4) within irrigation, and combinations of each. Products were applied over 13 weeks at Clemson University horticulture greenhouses with samples taken at thatch depth, 0-5.1 cm below thatch, and 5.1-10.2 cm below thatch at conclusion of study. Average Cu concentrations in thatch layer was 634.7 kg Cu ha-1, with 0 - 5.1 cm and 5.1 - 10.2 cm depth concentrations of 11.26 and 6.84 kg Cu ha-1, respectively. Remediation studies exposed 5 mg Cecil sandy loam to 15 ml 1000 ppm of CuSo4-Cu followed by 4 sequential 20 ml filtration cycles of 1 N ammonium sulfate, 1 N calcium nitrate, 1 N gypsum, or water. Single filtration of ammonium sulfate removed similar or greater amount of Cu than cumulative impact of 4 filtrations of any other products with 2064 mg Cu kg-1. Studies suggest that the management or removal of thatch may alleviate toxic accumulation of copper, however the use of ammonium sulfate in irrigation water may provide additional remediation options to turfgrass managers.

Evaluation of the toxic metals, proximate composition and length-weight relationships of selected fish species from the Gadananathi River, Southern Tamil Nadu.

The present study reveals toxic metals, proximate composition, and growth conditions in seven fish species, aiding their nutritional importance and conditions. The samples of seven different small indigenous fish species, including Xenentodon cancila, Glossogobious giuris, Pseudambassis ranga, Puntius dorsolis, Mystus vittatus, Dawkinsia filamentosa, and Dawkinsia tambraparaniei, were collected in river Gadananathi, Tamilnadu, India. A total 14 fish samples were analyzed for lead, cadmium, and copper using atomic absorption spectrometry. The standard procedures were used to determine the length-weight and proximate composition of the seven fishes. The findings revealed that the seven fish species had variable amounts of metal buildup. Cu levels were highest in D. tambraparniei gills and lowest in M. vittatus gills and livers; nonetheless, substantial amounts of Cu were found in P. dorsalis livers. In the length-weight correlations of the regression parameters of coefficient value r2, the "a" and "b" values revealed a positive allometric growth rate in all fish species except G. giuris and M. vittatus. However, X. cancila had the highest composition in the proximate analysis, while D. tambraparniei and D. filamentosa had the highest protein content mean value at a significant level (P ≤ 0.05). Overall, discrepancies in nutritional content might be related to species, environmental circumstances, fish age and size, and food availability.

Fe2−xCuxSnS4: Synthesis, structure and magnetic properties of a series of disordered spinels

Quaternary chalcogenides of compositions Fe2−xCuxSnS4 (x = 0.3, 0.4, 0.5, 0.6, 0.7) were synthesized at high temperature, 800 °C, in a sealed silica tube. All the compounds crystallized in the spinel structure type with cubic Fd−3 m space group. Both magnetic and nonmagnetic ions are disordered in these compounds with Fe/Sn occupies half of the octahedral voids while Fe/Cu occupies 1/8th of the tetrahedral voids as obtained from the Rietveld refinement of powder X-ray diffraction data. XPS study indicates that Fe exists in both +2 and + 3 oxidation states while Cu, Sn and S adopt +1, +4 and −2 oxidation states, respectively. Magnetic susceptibility study suggests ferrimagnetic like ordering in Fe1.6Cu0.4SnS4 below 230 K and the ordering temperature gradually decreases from 230 K to about 120 K with increase in Cu substitution. As the amount of Cu(I) increases in Fe2−xCuxSnS4, the percentage of Fe(III) increases to balance the charge. The magnetocaloric properties of polycrystalline Fe1.6Cu0.4SnS4 has been studied for their potential applications as magnetic refrigerant at cryogenic temperatures. With an applied magnetic field of 5 T, the maximum value of magnetic entropy change was found to be (Δ Sm) 0.4 Jkg−1K−1 with a relative cooling power (RCP) of 7 J kg−1. These values are very similar to the literature reported values for Fe based compounds. Further, manipulation at the Fe site may lead to enhancement of magnetocaloric effect for practical applications.

Influence of substituting Cu2+ for Zn2+ on the crystal structure and terahertz dielectric performances of Zn1-xCuxZrNb2O8 (x = 0.000–0.050) ceramics

A series of Zn1-xCuxZrNb2O8 (x = 0.000, 0.003, 0.010, and 0.050) ceramics with low dielectric loss and intermediate dielectric constants were synthesized by a conventional solid-phase reaction method. The terahertz dielectric performances of Zn1-xCuxZrNb2O8 (x = 0.000, 0.003, 0.010, and 0.050) ceramics have been investigated by using the Rietveld refinement method, scanning electron microscopy, Raman spectroscopy, and terahertz time-domain spectroscopy. The microscopic morphology analysis shows that the appropriate amount of Cu2+ content can make the specimen have the most uniform and medium-sized grains, which can minimize the dielectric loss in the terahertz range. Raman mapping reveals that the stress distribution is not uniform in different grains or in different regions of the same grain. The internal stresses affect the interatomic distances and influence the electronic properties, thus increasing the lattice anharmonicity and dielectric losses. In addition, the dielectric constant of the specimen in the terahertz range is mainly determined by the ionic polarization. For Zn0.997Cu0.003ZrNb2O8 sintered at 1240 °C, low dielectric losses (< 4 × 10−3 @ 0.40 THz) and intermediate dielectric constant (∼22.95 @ 0.40 THz) were obtained, which make it promising for applications in terahertz dielectric filters.

Biological Renewable Cellulose-Templated Zn1-XCuXO/Ag2O Nanocomposite Photocatalysts for the Degradation of Methylene Blue.

Herein, Cellulose-templated Zn1-XCuXO/Ag2O nanocomposites were prepared using biological renewable cellulose extracted from water hyacinth (Eichhornia crassipes). Cellulose-templated Cu-doped ZnO catalysts with different amounts of Cu as the dopants (1, 2, 3, and 4%) were prepared and denoted CZ-1, CZ-2, CZ-3, and CZ-4, respectively, for simplicity. The prepared catalysts were tested for the degradation of methylene blue (MB), and 2% Cu-doped ZnO (CZ-2) showed the best catalytic performance (82%), while the pure ZnO, CZ-1, CZ-3, and CZ-4 catalysts exhibited MB dye degradation efficiencies of 54, 63, 65, and 60%, respectively. The best catalyst (CZ-2) was chosen to further improve the degradation efficiency. Different amounts of AgNO3 (10, 15, 30, and 45 mg) were used for the deposition of Ag2O on the surface of CZ-2 and denoted CZA-10, CZA-15, CZA-30, and CZA-45, respectively. Among the composite catalysts, CZA-15 showed remarkable degradation efficiency and degraded 94% of MB, while the CZA-10, CZA-30, and CZA-45 catalysts showed 90, 81, and 79% degradation efficiencies, respectively, under visible light within 100 min of irradiation. The enhanced catalytic performance could be due to the smaller particle size, the higher electron and hole separation and charge transfer efficiencies, and the lower agglomeration in the composite catalyst system. The results also demonstrated that the Cu-doped ZnO prepared with cellulose as a template, followed by the optimum amount of Ag2O deposition, could have promising applications in the degradation of organic pollutants.

A Long-Term Study on the Bactericidal Effect of ZrN-Cu Nanostructured Coatings Deposited by an Industrial Physical Vapor Deposition System.

ZrN-Cu coatings containing two different amounts of Cu (~11 at.% and ~25 at.%) were deposited using an industrial physical vapor deposition (PVD) system. The as-deposited coatings exhibited 100% bactericidal efficiency against Escherichia coli CCM 3988 for an exposure time of 40 min. Subsequently, the samples were attached onto our faculty's door handles for six months to study the coatings' long-term effectiveness and durability under actual operational conditions. The samples were periodically evaluated and it was observed that the coatings with 25 at.% Cu performed better than the ones with 11 at.% Cu. For example, following 15 days of being touched, the bactericidal effectiveness of the sample containing 25 at.% Cu dropped to 65% while it fell to 42% for the sample containing 11 at.%. After 6 months, however, both samples showed bactericidal efficiency of ~16-20%. The bactericidal efficiency of the samples touched for 6 months was successfully restored by polishing them. Furthermore, a group of samples was kept untouched and was also evaluated. The untouched samples with Cu content of ~25 at.% did not show any drop in their bactericidal properties after 6 months. ZrN-Cu coatings were concluded to be promising materials for self-sanitizing application on high-touch surfaces.

Improved Charge Carrier Transport Across Grain Boundaries in N‐type PbSe by Dopant Segregation

Doping is an important and routine method to tune the properties of semiconductors. Dopants accumulated at grain boundaries (GBs) can exert a profound influence on microstructures and transport properties of heat and charge. To unravel the effect of dopant accumulation at GBs on the scattering of electrons, individual high‐angle GBs in three PbSe samples doped with different amounts of Cu using a home‐designed correlative characterization platform combining electron backscatter diffraction, microcircuit transport property measurements, and atom probe tomography are studied. The findings reveal that the segregation of Cu dopants to GBs reduces the GB potential barrier height. Once the GB phase reaches an equilibrium with saturated Cu, the extra Cu dopants distribute homogeneously inside the grains, compensating for vacancies and improving the electrical conductivity of the PbSe grains. The results correlate the Cu distribution at GBs and grains with local electrical properties, enlightening strategies for manipulating advanced functional materials by GB segregation engineering.

ADSORPTION CAPACITY OF CARBONIZED TITONIA DIVERSIFOLIA TOWARDS Cd2+ AND CU2+ UNDER DIFFERENT pH, ADSORPTION CAPACITY AND CONCENTRATION

Adsorption studies were performed to investigate the adsorption capacity of carbonized Tithonia diversifolia towards heavy metal ions (Cd2+ and Cu2+) under different pH, contact time, concentration and temperature conditions. Cadmium metal concentrations at; 25 ppm, 50 ppm, 75 ppm, 100 ppm, 150 ppm and 200 ppm of metal solutions were prepared and the pH was adjusted to 5. The uptake of copper (II) increases as the pH of the solution increases; at pH 1, pH 2, pH 3, pH 4 and pH 5, percentage metal bound were 20.59, 48.47, 94.26 and 94.08% respectively, at pH 5 and pH 6, percentage metal bound dropped to 93.26, 92.62% respectively. The increase in the removal of copper as pH increases is attributed to the decrease in competition between proton and Cu2+ ion for the surface site. Cadmium study showed that the optimum binding pH is 5 while at pH 1, pH 2, pH 3, pH4 and pH 6, percentage bound were 25.59, 59.12, 96.76, 96.14 and 98.31% respectively. The percentage removal for cadmium (II) ion is low at pH 1 and remains high and almost constant at pH 6. The high binding power of cadmium (II) ion at the initial stage is attributed to the biomass having maximum binding sites available for interaction. Our findings showed that the amount of Cu+2 and Cd2+ adsorbed was found to vary with the initial solution pH, adsorbent dosage and concentration.